One advantage of Shopify over some other shopping carts is how easy it is to change the text on your site. What I mean is the bits of language that tell people what to do and where stuff is, or gives them instructions or error messages.
For example, at checkout there is a checkbox that can let people sign up for your newsletter as they check out.
You can edit the words here to say whatever you want. “Sign up for our newsletter” can become “Sign up for our monthly newsletter and save 10% on your next order.”
Language variables like this are tied to your theme. You get to them by going to your Online Store, then Themes, then click the “. . .” dropdown and select “Edit Language.” There are a LOT of possible things to change. For this, you’re looking in the very last tab (which might be hidden) for the “checkout/system” options. And then you’re looking way down near the bottom…